Hydraulic Tappet Replacement
The tappets were really loud on the 944, one of them had collapsed and made a loud metallic noise whenever the car was stood for long periods of time.
I used the video irina25661 to help me figure out what I needed to tackle the job, and the whole job is detailed in the the article in Clark’s Garage website. The camshaft chain tensioner guide is also here
Removing the lifters is a complicated process as the all the belts need removing, the camshaft pulley and the rocker cover as well as the cam towers. I did a post showing how to remove the bel
The 944 lifters are really expensive at £80 a lifter and you need 16 to replace the all and few guys on the 944 forum have had success replacing them with VR6 8v lifters which are much cheaper at £160 for a full set of 16 INA ones. The comparison of the lifters is below
These is a load of information on replacement tappets on the Porsche Club Forum I got some INA 420002210 tappets from AUTODOC.
Removing the lifters is a complicated process as the all the belts need removing, the camshaft pulley and the rocker cover as well as the cam towers. I did a post showing how to remove the bel
To remove the cam tower bolts you need a 8mm 12 point splined socket. The bolts are only torqued down to 20nm but after 35 years in place they did not what to come out and eight out of the 16 bolts stripped the spines.
I used my bolt grip extractor tool which easily pulled out the problematic bolts. However getting replacement was a problem as they are on back order with Design 911, I tried a nut & bolt specialist rather that ordering online because of the long wait, but the head on these bolt and very small and the cam cover would not fit on so I had to order some from RosePassion Porsche parts specialist in France.
The tappets fitted prefectly and slid into place on a bit of oil was applied to them. Don’t forget to block the oil ways with some rags to stop any bits flying down the oil ways.
With the cams out I could fit a new timing chain, the new chain came with two different coloured links that are used to align the cam chain markers with.
Put the cam back in with the marker in the vertical position.
The camshaft timing gear covers where both screwed on my 944, I had previously had put some helicoils in the front cover as the bolt holes disintegrated when I tried to put it back in place and the mounting point snapped on the rear cover when I did the belts back in May 2024.
A new rear cover was sourced from YouTrade 944 in Poland via eBay for £80, it took me two months of checking as these are impossible to find, there are lots of front covers which are easy to find for about £50 from eBay. I transfers the camshaft timing sensor on to the new rear cover and fitting to the car
While I had the timing and balance shaft belts off I decided to change the water pump. I was unable to get the whole 7.5 litres of coolant, maybe 5 litres came out from the radiator and expansion tank. However 7.5 litre went back in.
As I planned to used Evans Waterless I had to add the preparation fuild to get rid of all traces of water and then add the red waterless coolant. While the water was out the car I changed the water pipes for some silicon ones.
While the engine ran a lot smoother and quieter there was still a light ticking noise. I suspected this was due to the state of the cylinder bores as at 156k they will be worn. I quick check with a bore scope confirmed this.
So it was time to split engine and check out the head and work out what to do next 😵💫
